This invention relates generally to vehicle mirrors incorporating wipers for keeping the mirror surface visually clear and, more particularly, to an improved wiping mirror that employs a simpler, less costly mechanism for providing oscillating wiper movement.
Various wiping mirrors are known in the prior art. Exemplary of such wiping mirrors is that described in U.S. Pat. No. 4,873,740 to Vahrenwald et al., which utilizes a specialized level wound screw rotationally driven in a single direction. The presence of both left and right hand helix threads on such a screw causes the attached wiping mirror to reverse its direction of travel each time its reaches its limit of travel at either end of the screw. Not only is the mechanism of Vahrenwald et al. expensive to fabricate, but it is also maintenance intensive as a result of gears and other rapidly wearing parts. Moreover, this mechanism is susceptible to jamming whenever motion is halted during a wiping cycle, as frequently occurs in intermittent wiper applications.
It is therefore the principal object of the present invention to provide an improved wiping mirror for trucks and other motor vehicles that is less expensive to produce and more reliable to operate than prior art wiping mirrors.
This and other objects are accomplished in accordance with the illustrated preferred embodiment of the present invention by providing a wiper carrier coupled to an off-the-shelf multiple start, high lead screw that is driven by a reversing motor. A magnetic switch positioned adjacent each end of the screw senses the approaching wiper carrier and reverses its direction of travel by reversing the motor.